Hkoenig optiV8 Manuel D'instructions page 11

Replacement of filter
Method: SIide water tank out from base unit, take the filter out from water tank, and then replace
with a new one. After new filter has been installed well into water tank, fill water into water tank
to Max fill level, and then slide water tank back into base unit. (Immerse filter in water for several
minutes in order to gain better performance in future use.